Ceramics-Silikáty 45 (4) 129-136 (2001)

THE IMPACT OF BUBBLE ARRAYS ON GLASS FLOW AND REDOX STATE OF GLASS DURING GLASS MELTING

 L. Němec, M. Jiřička, J. Matyáš, A. Franěk

The bubble arrays present in the glass melting spaces may extract gases from the melt and thus decrease its refining ability, as well as influence glass flow by changing density of the mixture glass melt-bubbles. Both phenomena were examined using the 3D and 2D models. The examination of the bubble extraction ability on elected glass pathways in the 3D model has shown that refining gases were evidently removed from the reduced glass melt (amber) while the concentration drop of dissolved refining gases in an oxidized glass was negligible. The distinct bubble stirring effect in the 2D melting space was observed when inputting about 3 vol.% of small bubbles (a = 2.5x10^-4 m) through a part of bottom. The effect of bubble concentration gradients on the intensity of glass convection was analogical to the impact of temperature gradients on glass flow in case of temperature convection. Different behavior was observed, however, when examining the impact of geometrical shape on the melt flow. Both described phenomena should be considered in advanced mathematical models of glass melting spaces.

Keywords: Bubble, Glass flow, Redox state